New Jersey Gov. Chris Christie, who tips the scale at an estimated 290 pounds, must be slipping on his diet. He popped into East 54th Street Italian power-dining spot Cellini on Monday night with his wife Mary Pat, son Andrew and an unidentified priest. Spies say corpulent Christie, 49, and his party took an alcove table on the side. The gov first dug into a spread of cheesy focaccia and bruschetta. Next, he worked on a shared platter of pork sausage. “Finally,” said a regular, “He ordered lasagna bolognese, a huge portion made with beef and pork. It has to be a gajillion calories. The hilarious thing was, he only drank a couple of Diet Cokes.” His slender wife had branzino. Christie, 5-feet-11, whose precise weight has never been revealed, told CNN’s Piers Morgan he was “struggling” with his girth in June. He was later hospitalized for asthma and is reportedly working with a personal trainer. The group got up to leave Cellini at about 8:45 p.m., with the gov gamely posing for photos with adoring customers.